As a class of environmentally concerning contaminant elements, heavy metals include transition metals and metalloids. Heavy metals are often discharged into the environment through, for example, industrial process waters, mining effluents, organic wastes, and waste burning. Heavy metals can be toxic, even at low levels, to humans, animals, and plants. For environmental, public health, and economic reasons, it may be beneficial to efficiently and safely remove the heavy metals from the solution sources.
There remain ongoing needs for chemical compounds capable of removing heavy metals from solution streams or waters. There remain further needs for methods for preparing such compounds, methods for removing heavy metals from solutions by using such compounds, filtration apparatus, and methods such as batch methods that use such compounds as an active ingredient.